Disposable syringes are in widespread use for a number of different types of applications. For example, syringes are used not only to withdraw a fluid (e.g., blood) from a patient but also to administer a medication to a patient. In the latter, a cap or the like is removed from the syringe and a unit dose of the medication is carefully measured and then injected or otherwise disposed within the syringe.
As technology advances, more and more sophisticated, automated systems are being developed for preparing and delivering medications by integrating a number of different stations, with one or more specific tasks being performed at each station. For example, one type of exemplary automated system operates as a syringe filling apparatus that receives user inputted information, such as the type of medication, the volume of the medication and any mixing instructions, etc. The system then uses this inputted information to disperse the correct medication into the syringe up to the inputted volume.
In some instances, the medication that is to be delivered to the patient includes more than one pharmaceutical substance. For example, the medication can be a mixture of several components, such as several pharmaceutical substances.
By automating the medication preparation process, increased production and efficiency are achieved. This results in reduced production costs and also permits the system to operate over any time period of a given day with only limited operator intervention for manual inspection to ensure proper operation is being achieved. Such a system finds particular utility in settings, such as large hospitals, where a large number of doses of medications have to be prepared daily. Traditionally, these doses have been prepared manually in what is an exacting but tedious responsibility for a highly skilled staff. In order to be valuable, automated systems must maintain the exacting standards set by medical regulatory bodies, while at the same time simplifying the overall process and reducing the time necessary for preparing the medications.
Because syringes are often used as the carrier means for transporting and delivering the medication to the patient, it is advantageous for these automated systems to be tailored to accept syringes. However, the previous methods of dispersing the medication from the vial and into the syringe were very time consuming and labor intensive. More specifically, medications and the like are typically stored in a vial that is sealed with a safety cap or the like. In conventional medication preparation, a trained person retrieves the correct vial from a storage cabinet or the like, confirms the contents and then removes the safety cap manually. This is typically done by simply popping the safety cap off with ones hands. Once the safety cap is removed, the trained person inspects the integrity of the membrane and cleans the membrane. An instrument, e.g., a needle, is then used to pierce the membrane and withdraw the medication contained in the vial. The withdrawn medication is then placed into a syringe to permit subsequent administration of the medication from the syringe. In many cases, the medication in the vial is powdered and must be reconstituted by the addition of a liquid diluent. In this case, the process includes first injecting diluent into the vial, agitating the vial to liquefy its contents, and then removing the liquefied medication from the vial as previously described.
FIG. 1 illustrates an exemplary conventional syringe 10 that includes a barrel 20 having an elongated body 22 that defines a chamber 30 that receives and holds a medication that is disposed at a later time. The barrel 20 has an open proximal end 24 with a flange 25 being formed thereat and it also includes an opposing distal end 26 that has a barrel tip 28 that has a passageway 29 formed therethrough. The passageway 29 is an ANSI standard male luer fitting. One end of the passageway 29 opens into the chamber 30 to provide communication between the barrel tip 28 and the chamber 30 and the opposing end of the passageway 29 is open to permit the medication to be dispensed through a cannula (not shown) or the like that is later coupled to the barrel tip 28.
An outer surface of the barrel tip 28 can include features to permit fastening with a cap or other type of enclosing member. For example, the outer surface can have threads 27 that permit a tip cap 40 to be securely and removably coupled to the barrel tip 28. The tip cap 40 thus has complementary fastening features that permit it to be securely coupled to the barrel tip 28. The tip cap 40 is constructed so that it closes off the passageway 29 to permit the syringe 10 to be stored and/or transported with a predetermined amount of medication disposed within the chamber 30. As previously mentioned, the term “medication” refers to a medicinal preparation for administration to a patient and most often, the medication is contained within the chamber 30 in a liquid state even though the medication initially may have been in a solid state, which was compounded or processed into a liquid state.
The syringe 10 further includes a plunger 50 that is removably and adjustably disposed within the barrel 20. More specifically, the plunger 50 is also an elongated member that has a proximal end 52 that terminates in a flange 54 to permit a user to easily grip and manipulate the plunger 50 within the barrel 20. Preferably, the plunger flange 54 is slightly smaller than the barrel flange 25 so that the user can place several fingers around, against, or near the barrel flange 25 to hold the barrel 20 and then use fingers of the other hand to withdraw or the thumb of the certain hand to push the plunger 50 forward within the barrel 20. An opposite distal end 56 of the plunger 50 terminates in a stopper 59 or the like that seals against the inner surface of the barrel 20 within the chamber 30. The plunger 50 can draw a fluid (e.g., air or a liquid) into the chamber 30 by withdrawing the plunger 50 from an initial position where the stopper 59 is near or at the barrel tip 28 to a position where the stopper 59 is near the proximal end 24 of the barrel 20. Conversely, the plunger 50 can be used to expel or dispense medication by first withdrawing the plunger 50 to a predetermined location, filling the chamber 30 with medication and then applying force against the flange 54 so as to move the plunger 50 forward within the chamber 30, resulting in a decrease in the volume of the chamber 30 and therefore causing the medication to be forced into and out of the barrel tip 28.
As shown in FIG. 2, a conventional vial 60 is formed of a body 62 (i.e., glass) and is sealed with a membrane (septum) 64 across the open end 66 of the body 62. The membrane 64 can be formed of any type of material that is typically used in this setting for sealing a container (e.g., vial 60) yet at the same time permit a user to puncture or pierce the membrane 64 with an instrument to gain access to the inside of the container. In one exemplary embodiment, the membrane 64 is formed of a rubber material that fits across the open end 66 while still providing the necessary seal.
The membrane 64 is securely held in place across the open end 66 by a retainer ring 68 that is itself securely attached to the body 62. The retainer ring 68 circumferentially surrounds a neck formed at the open end 66 and includes an upper section that seats against an upper surface of the membrane 64 and a lower section that engages the body 62 underneath the neck. The retainer ring 68 is open in a middle section thereof such that when the retainer ring 68 is securely attached to the body 62, the retainer ring 68 holds the membrane 64 in place with the membrane 64 being visible in the open middle section of the retainer ring 68. The retainer ring 68 can be attached to the body 62 using any number of conventional techniques, including a crimping process, so long as the retainer ring 68 securely holds the membrane 64 such that a seal results between the open end 66 and the membrane 64.
A safety cap 70 is securely attached to the vial 60 to cover the exposed membrane 64 and further seal the open end 66 of the vial body 62. The safety cap 70 is typically formed of a light, disposable material, such as a plastic, and is attached to retainer ring 68 in a tamper proof manner. For example, the safety cap 70 is attached so that once it is removed, it can not be re-attached to the retainer ring 68. In any event and unless the exact history of the particular vial is know, any vial that is missing a safety cap 70 is ordinarily discarded and not used.
The safety cap 70 is a solid member that extends completely across the exposed portion of the membrane 64 and, preferably, the peripheral edges of the safety cap 70 are downwardly curved so that the peripheral edges overlap the outer peripheral edges of the retainer ring 68. The safety cap 70 contains features that permit it to be attached to the retainer ring 68. One skilled in the art understands the various means of securing the safety cap 70 to the retainer ring 68 and therefore these means are not discussed in any great detail.
Typically, the medication is placed in the syringe when the needle is in place and secured to the barrel tip by drawing the medication through the needle and into the syringe barrel. Such an arrangement makes it very difficult for this type of syringe to be used in an automated system due to the fact that medication is drawn through the small needle into the syringe barrel and therefore this operation is a very time and labor intensive task. What is needed in the art and has heretofore not been available is a system and method for automating the medication preparation process and more specifically, an automated system and method for preparing a syringe including the withdrawal of the syringe plunger.